Questions on Algebra: Quadratic Equation answered by real tutors!

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Question 373661: I need to solve these quadratic equations using the method that came from India. I am confused.
The sample problem is:
xsquared + 3x -10 = 0
The solution reads as follows, but I do not understand it.
x squared + 3x = 10
4x squared + 12x = 40
4x squared + 12x +9 = 40 + 9
4x squared + 12x +9 = 49
2x + 3 = +-7
2x + 3 = 7
2x = 4
x = 2
and
2x + 3 = -7
2x = -10
x = -5
Is there anyway you can explain this method to me? I do not understand where the x squared turned into the 4x squared and where the 12x went later in the problem. Thank you in advance for your help.
Click here to see answer by solver91311(24713)

Question 373705: How to solve 2x^2 + 7 = 61 and 5z^2-200 = 0
Thank you very much
Click here to see answer by ewatrrr(24785)

Question 373715: using the discriminant, how many times does the graph of this equation cross the x-axis?
2x^2+6x-3=0
im not looking for the answer just explain the steps please?
Click here to see answer by Fombitz(32388)

Question 373739: at^2+bt+c=0
Click here to see answer by Fombitz(32388)

Question 373895: For all values of n and r, where r ≤ n, does nCr always equal nCn-r? Why or why not?
NO? I am so confused
Click here to see answer by robertb(5830)

Question 373865: Find a value of the variable that shows that the two expressions are not equivalent. Answers may vary.
a + 7 / 7 ;a
Click here to see answer by Fombitz(32388)

Question 373884: A positive integer is 11 more than 5 times another. The product is 988. Find the two integers using the quadratic formula.
Click here to see answer by mananth(16946)

Question 373974: Write a quadratic equation for -7,5
Click here to see answer by nerdybill(7384)

Question 373971: help me solve this, please. 7x+x(x-5)=0. I'm not sure what to put in place of the x
Click here to see answer by nerdybill(7384)

Question 373975: Determine nature of solution
y^2=3/4y+4/7
Click here to see answer by Fombitz(32388)

Question 373986: Find all roots by factoring: f(x)=x^3+7x^2+10x
Click here to see answer by Earlsdon(6294)

Question 373991: Please help me solve this equation [6xsquare +11x+60}
Click here to see answer by jim_thompson5910(35256)

Question 374147: Find a quadratic equation for each root.
a)(2/3,-5)
b)(-1/2,-3/4)
c)(0,-3/2)
d)2+root5,2-root5
Click here to see answer by edjones(8007)

Question 374113: Can you help me solve this problem.
Our topic is about quadratic equations by completing the square.
The product of two numbers is 10 less than 16 times the smaller.If twice the smaller is 5 more than the larger number, find the two numbers.
Click here to see answer by scott8148(6628)

Question 374191: When the square of a certain number is diminished by 9 times the number the result is 36. Find the number.
Click here to see answer by Bebita1992(4)

Question 374107: the area of a carpet is 308 sq m .If its length is 2 meters less and its width 6 meters more,the carpet will be square.Find the dimensions of the carpet.
P.S Solving Quadratic Equations by Completing the Square is the topic.

Click here to see answer by amoresroy(361)

Question 374235: Can you help me solve this problem please!
topic:quadratic equations by completing the square
marivic is five years older than michelle. in three years , the prdocut of her age and michelle's age five years ago will be 90 years.Find their present ages.
Click here to see answer by mananth(16946)

Question 374365: Determine the nature of the solutions of the equation X2-3x+9=0
A: one real solution
B: two non-real solutions
C: two real solutions

Click here to see answer by jsmallt9(3758)

Question 374363: Determine the nature of the solutions of the equation x2-4=0.
A: 1 real solution
B: 2 real solutions
C: 2 imaginary solutions

Click here to see answer by jsmallt9(3758)

Question 374485: I thought you used the formula -b+-sqroot b^2-4ac/2a My answer did not look right, please help!
Solve.
15x^4-11x^2+2=0
Click here to see answer by Alan3354(69443)

Question 374490: w^2+50w�6600=0
Click here to see answer by jim_thompson5910(35256)

Question 374567: write a quadratic equation in the variable x having the given numbers as solutions. SOLUTION: 2, ONLY SOLUTION
Click here to see answer by robertb(5830)

Question 374641: A rectangle is 9ft longer than its wide, and its area is 360ft2. use quadratic equation to find its length and width
Click here to see answer by mananth(16946)

Question 374408: Use the quadratic formula to find all roots: f(x)= 2x^3-3x^2-2x+3
Click here to see answer by ankor@dixie-net.com(22740)

Question 374913: Is this the solution to this problem:
2.Discriminant is zero. There is only one solution.
x = -b/2a

Click here to see answer by ewatrrr(24785)

Question 374923: Solve the equation x^2-4x=-10 and express the roots in terms of i.
Click here to see answer by Fombitz(32388)

Question 374974: Evening Everyone.
Been a while since i attempeted anything like this and trying to brush up a little, i have attempted to anser the first two parts if somebody would be so kind as to check them and assist on the third part

Use the chain rule to find the derivatives of the following functions:
(a) y = e^-x2
I Got = -2e^(-x^2)
(b) y = cos(3x^2 + 2x)
I Got = (-Sin).(3x^2+2x).(6x+2)
(c) y = sin^2(3x^2 - 1)
Thank You in antiscipation
Click here to see answer by Fombitz(32388)

Question 375002: Would really appreciate help with the following question on my task sheet.

Find dy=dx as a function of x and y when:
(a) y - x sin y - 3x^2 - 1 = 0
and
(ii) x^2y^3 - x^2 + 3y - 3 = 0
Finally
(c) (1 - x^2) tan^-1 y = 3
Need to brush up on these, have looked in engineering mathmatics book, having difficulty, and the instructor isnt really approachable
Thanks
Click here to see answer by Fombitz(32388)

Question 375008: HiPlease can somebody help with this problem i) The variables x and y are given in terms of the parameter t as x = 3t(1 + t^3) and y = 3t^2(1 + t^3). Provethat dy/dx = t(2 + 5t^3)/1 + 4t^3 ii) A cycloid is a curve traced out by a point on the rim of a wheel as it rolls along the ground. Its curve maybe given parametrically by x = a(t - sin t) and y = a(1 - cos t), where a is a constant. Show thatdy/dx = cot(t/2) Thanks
Click here to see answer by Fombitz(32388)

Question 375016: I don't know how to convert this equation into standard form (i'm completely lost):
150=w[(120-w)/2]
thank you
Click here to see answer by solver91311(24713)

Question 375026: 48-Y=X=128/Y
Click here to see answer by Fombitz(32388)

Question 375035: What 2 numbers have a product of 128 and a sum of 48?
I don't believe it has a solution with whole numbers anyway.

Click here to see answer by jim_thompson5910(35256)

Question 375015: Hi Totally Bewildered, Please Help?

The path of a point is given parametrically by x = a cos t, y = b sin t. Show that the point travels
around the ellipse
x^2/a^2 +y^2/b^2 = 1
Express dy=dx in terms of t. Suppose that t represents time. Express the speed as a function of t.
ii) A closed hollow vessel is in the form of a right-circular cone, together with its base, and is made of sheet
metal of negligible thickness.
Express the total surface area S in terms of the volume V and the semi-vertical angle 'theta' of the cone.
Show that for a given volume, the total area of the surface is a minimum if sin 'theta' = 1/3 . With this value of 'theta', find
the value of S if V = 8/3'pie' a^3 where a is a constant.
Sorry didnt know how to get symbols on this, so typed the names
Kind Regards
John
Click here to see answer by solver91311(24713)

Question 375065: Hello everyone, finding the following question puzzling, i have not covered this before, and am trying to get a heads up for when i start my course
Use logarithmic differentiation to differentiate the following:
(i) y = 2^x (ii) y = x^x
Cheers
Click here to see answer by jim_thompson5910(35256)

Question 375143: Solve the system of equations by graphing. Then clasify the system.
6u=v= 32
6u=v=40
Click here to see answer by robertb(5830)

Question 375143: Solve the system of equations by graphing. Then clasify the system.
6u=v= 32
6u=v=40
Click here to see answer by Alan3354(69443)

Question 375139: Solve the system of equations by graphing. Then classify the system.
6x-y=21
6x=7y=-3
Click here to see answer by Fombitz(32388)

Question 375243: how do solve: h(t) = -16t^2 + 90t + 15
Click here to see answer by nerdybill(7384)

Question 375234: x(2x+7)=0
Click here to see answer by Fombitz(32388)

Question 375377: What is -3x^2+12x in vertex form?
Click here to see answer by Fombitz(32388)

Question 375397: a student is asked to solve b^2+x^2=a^2 and gives the solution:x=a-b. What did they do wrong and how do you correctly solve this????

Click here to see answer by edjones(8007)

Question 375466: factor quadratic expression
3. 5x2 � 19x � 4
Click here to see answer by ewatrrr(24785)

Question 375465: factor each quadratic expression
2. 3x2 + 13x � 10

Click here to see answer by ewatrrr(24785)

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